Compact strip accumulator



April 14, 1970 LA TO R ETAL 3,506,210

COMPACT STRIP ACGUMULATOR 2 Sheets-Sheet 2 Filed 001;. 20, 1967 INVENTOR/S HARRY LA 7002 AND GEORGED'M/LLE/Z,

' adwa, z% W -ATTO R'N E'YS.

United States Patent 3,506,210 COMPACT STRIP ACCUMULATOR Harry LaTour and George D. Miller, Middletown, Ohio, assignors to Arrneo Steel Corporation, Middletown, Ohio, a corporation of Ohio Filed Oct. 20, 1967, Ser. No. 676,808 Int. Cl. B65h 17/48 U.S. Cl. 242-55 25 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a compact and unique system for accumulating a continuous coil of strip material. The system is characterized by the absence of massive drive parts to effect coiling of the strip, and by its versatility and simplicity of operation. The accumulating device capable of practicing the method of this invention comprises a support upon which the strip material is acmulated by being coiled into two substantially concentric sets of convolutionsan outer set and an inner set-- connected by a free reverse loop which orbits between the sets of convolutions. The sets of convolutions are distinguished not only by their relative positions, but by their reversed winding which results in the existence of a numerical balance between the convolutions of the respective sets during periods of strip input and/or output from the device. That is, the rate of change in the number of convolutions in each set is the same, their number increasing as the quantity of the accumulated Strip increases and decreasing as the quantity decreases. To accommodate such changes without undesirable collapsing and slippage of the strip, the sets of convolutions are formed against expansible roll cages which support and guide the strip, the arrangement also making it possible to operate the system in any position from horizontal to vertical.

BACKGROUND OF THE INVENTION The present invention was developed as a means to eliminate the conventional loop tower, loop pit or horizontal loop car systems heretofore utilized to accumulate strip material. Such conventional systems are not only costly to construct and maintain, but they require a substantial amount of plant floor space and the time-storage capacity is narrowly limited so that they cannot be used for high speed production lines.

While it has hitherto been proposed to accumulate strip in coil form, as taught in U.S. Patents Nos. 3,258,212, 3,310,255 and 3,341,139, the accumulating devices taught in the above mentioned patents contemplate the accumulation of the strip in coiled condition on a table or similar support having one or more rotatable or driven portions which are utilized to control the accumulation of the strip. In contrast to such arrangements, a principal feature of the present invention lies in the elimination of variable speed rotatable tables and their inherent problems due to inertia, thereby materially simplifying the construction and operation of the accumulating device.

The present invention differs materially from the type of rotatable table devices which require a predetermined number of convolutions on the table at all times, which means that a substantial amount of strip must be maintained in the device at all times and taken into account when the device is operated. The present invention is omnidirectional and may be operated with an intermittent input and continuous output, or vice versa, with the result that no given quantity of strip need be maintained in the device. In other words, it is not necessary to initially store ice strip in the device, and it may be run anywhere between a completely empty to a completely full condition.

Whereas the rotatable or driven table accumulating devices produce considerable slippage between the convolutions of strip as they are operated, the present system may be operated with basically no slippage between the convolutions as they are formed or removed. This means that frictional contact and scratching between adjoining convolutions will be minimized.

Another distinguishing feature of the present invention lies in its unusual compactness as compared with conventional storage devices. This compactness is a result of the ability of the device to be operated in any position from horizontal to vertical, thereby requiring a minimum of plant floor space.

The system of the present invention has very low inertia which is increasingly important as speeds are increased. It may be further characterized by the absence of related differential speed drives-the coil having two sets of convolutions each of which may be rotated at any speed while the free loop automatically compensates for the difference.

SUMMARY OF THE INVENTION In the practice of this invention, there is provided a supporting structure in the nature of a table which, in one embodiment, comprises sets of radially extending edge confining rollers over which the strip passes as it is coiled. At the center of the supporting structure there is a circular cage of rollers around which the inner set of convolutions builds. Spaced outwardly from, and preferably substantially concentric with, the central cage of rollers, is a second cage of rollers which is adapted to contain and form the outer set of convolutions. The rollers in both cages are preferably movable in substantially radial paths to facilitate the build up in the number of convolutions in the two sets without slippage between the convolutions. While the roll cages are described as circular, other configurations may be used if desired. The two sets of convolutions normally will be concentric although this is not necessary as long as the freely orbiting loop has room to pass between the inner and outer sets of convolutions as it orbits.

The primary contact between the strip and the accumulating device is by means of the foregoing sets of cagedefining rollers all of which may be free-wheeling to minimize frictional resistance as the strip is fed to the device. The primary motive force for the strip being coiled is by means of a set of driven feed rolls which advance the incoming strip into contact with the outer roll cage. Strip is withdrawn from the device either by means of driven exit rolls or by tension exerted by the processing line to which the accumulated strip is being delivered. Other drive means, such as driven cage rollers, driven edge confiing rolls, or a rotating supporting structure, may be employed depending upon the size and structural details of a particular device. It is only necessary that the device be constructed in such a way that the inner set of convolutions can act in an essentially friction free, independent manner, with the added requirement that no obstruction be presented to the free loop.

The basic operating principle of the invention resides in the formation of a free reverse loop or strip which orbits in the space between the roll cages to form two sets of convolutions each having the same number of turns at any given time during either feeding or delivery. When the device is operated in a horizontal position, the coil will be disposed with the strip on edge on a supporting means, such as radially disposed edge confining rollers. In this case, the sets of cage-defining rollers merely serve as guides for the formation of the inner and outer sets of convolutions. When the system is operated on edge, i.e., where the radially disposed edge confining rollers lie in a substantially vertical plane, a second set of radially disposed edge confining rollers can be provided spaced from and parallel to the first set. That is, the strip will be accumulated in the space between the parallel planes of the two sets of edge confining rollers. In addition, the roll cages will act in part at least to support the weight of the sets of convolutions. To this end, the outer roll cage may be provided with enlarged non-movably mounted guide rollers along the bottom of the accumulator.

In the operation of the system, strip from a decoiler or from a preceding processing line is fed into the accumulating device by the set of driven feed rollers or other drive means positioned to feed the strip in essentially tangential relation to the outer roll cage. The strip is fed to the inside of the guide rollers which serve to guide the strip around the inner circumference of the rollers making up the outer cage. If it is assumed that the initial direction of feed is in a counterclockwise direction, a free reverse loop is made in the strip before the first outer convolution is completed, i.e., the direction of the strip is reversed and a clockwise winding is begun around the inner roll cage. For delivery of strip from the accumulating device, the leading end of the strip is passed around a roll forming a part of the inner roll cage and then around an angularly disposed exit roll at the center of the device from which the strip is fed to a succeeding portion of the strip processing line.

Once the strip has been threaded through the device in the manner described, strip will be accumulated by feeding it into the device at a greater lineal rate than it is being withdrawn, such feeding movement causing the free reverse loop to move in an orbital path between the inner and outer sets of convolutions. A characteristic of the system is the numerical balance between the inner and outer sets of convolutions. For each convolution of strip added to the outer set of convolutions during accumulation, a convolution will also be added to the inner set by the orbiting reverse loop. Conversely, when strip is withdrawn from the device, the orbiting loop changes its direction of movement and for each convolution withdrawn from the inner set, a proportional length of strip will be withdrawn from the outer set and the numerical balance between the sets of convolutions will remain the same. Another characteristic of the system is that the outer set of convolutions rotates only when strip is supplied to the accumulator and the inner set of convolutions rotates only when strip is delivered from the accumulator. If, for example, the delivery of strip from the device is stopped but the feed to the device is continued, the entire outer set of convolutions will rotate and the orbiting reverse loop formed between the inner and outer sets of convolutions will move in a counterclockwise direction, i.e., in the direction of initial feed, and with each revolution of the orbiting loop one convolution of strip will be concurrently added to both the inner and outer sets of convolutions. On the other hand, if the feed is stopped and the delivery of strip from the device is continued, the entire inner set of convolutions will be rotated in a clockwise direction by the strip being with drawn, and the reverse loop will also orbit in a clockwise direction, i.e., in the direction opposed to the initial feed, as a strip is also peeled from the inside of the outer set of convolutions. The direction of movement of the orbiting loop is determined by the net lineal speed of the feed and delivery of the strip.

As noted above, the feed of strip is to the outside of the outer set of convolutions; thus, succeeding strip is fed between the rollers defining the outer roll cage and the outermost convolution of the outer set. The feeding of the strip is facilitated by mounting the guide rollers making up the outer roll cage for limited movement in a substantially radial path, thereby effectively permitting the diameter of the outer roll cage to increase as additional convolutions are added to the outer set. The guide 4 rollers may be mounted to move independently of each other, although preferably they will be linked together for joint movement. The movement of the guide rollers may be such as to result in either circular or elliptical sets of convolutions. In some cases it may be desirable to maintain circular rather than elliptical convolutions to minimize flexing when operating at high speeds. By linking the guide rollers for joint movement, the thrust of the incoming strip will be uniformly transferred to the other guide rollers. In an embodiment where the guide rolls are non-movably mounted in the area at which the strip enters the device, the increase in the diameter of the outer set of convolutions is compensated for by mounting the rollers on the opposite side of the cage for a greater degree of radial movement than those which are closer to the non-movable guide rollers.

The guide rollers in the inner roll cage also may be movably mounted, being urged radially outwardly so that, as the innermost convolutions are removed the inner roll cage will grow in diameter to prevent collapsing of the remaining convolutions which, in turn, prevents slippage between the convolutions.

The accumulator of this invention has wide application and can be operated at strip speeds of up to several thousand feet per minute, and consequently it has no practical speed limitation. The system can handle strip of essentially any gauge or width in any desired position.

DESCRIPTION OF THE DRAWINGS FIGURE 1 is a front view of a strip accumulator in accordance with the instant invention, the accumulator being operated in a substantially vertical position.

FIGURE 2 is a sectional view taken along the line 22 of FIGURE 1.

FIGURE 3 is an enlarged fragmentary sectional view taken along the line 3-3 of FIGURE 1.

FIGURE 4 is an enlarged sectional view taken along the line 44 of FIGURE 1.

FIGURE 5 is a schematic front view of the accumulator illustrating the manner in which the strip is initially threaded through the device.

FIGURE 6 is a schematic view similar to FIGURE 5 illustrating the manner in which convolutions are built up on both the inner and outer sets.

FIGURE 7 is a partial rear view illustrating the movable mounting of the rollers in the inner roll cage, with the rollers in their outermost position.

FIGURE 8 is a fragmentary rear view similar to FIG- URE 7 illustrating the rollers in their innermost position.

DETAILED DESCRIPTION OF THE DRAWINGS Referring first to FIGURE 1 of the drawings, the accumulating device, which is indicated generally at 1, comprises a base 10 mounting at centrally disposed circular support 11. The coil support in one embodiment of the invention comprises a series of radially disposed sets of edge confining rollers 12 and 12a projecting outwardly from the support 11, the sets of edge confining rollers being roatably journaled on shaft 12b, supported at their inner ends by brackets 13 mounted on the support 11 and at their outer ends by brackets 14 mounted on the base 10. Alternatively, the accumulated coil can be supported on a planar surface, such as an extension of the support 11, although rollers are preferred because of their anti-friction properties.

When it is desired to operate the device in a vertical position, a second series of radially disposed edge confining rollers 15 and 15a is provided adjacent to but in a plane spaced from the plane of edge confining rollers 12 and 12a. The clearance space C between the respective planes of the sets of edge confining rollers represents the approximate width of the strip material being stored. The rollers 15 and 15a preferably lie in interdigitating relation to the rollers 12 and 12a, being rotatably journaled on shafts 15b supported at their inner ends in brackets 16 mounted on support 11 and at their outer ends in elongated brackets 17 projecting outwardly from base 10. In the event it is desired to accumulate strip of differing widths, it is contemplated that the sets of edge confining rollers 12 and 12a and/or 15 and 15a may be adjusted relative to each other to produce a change in the width of clearance space C. As illustrated in FIG- URE 3, this may be accomplished by providing elongated slots 18 in the mounting brackets 16 and 17, with the shafts 15b of the rollers 15 and 15a adjustable along the slots, as by means of adjustment nuts 19.

The coil supporting surfaces are shown comprising edge supporting rollers 12 and 12a on one side of the coil and 15 and 15a on the other side. It will be understood that the rollers 12 and 12a, for example, are freely journaled so that they can rotate separately to accommodate the differential rotational speeds of the two sets of convolutions.

The device is provided with a centrally disposed abutment means in the form of an inner roller cage 20 composed of a plurality of guide rollers 21 mounted around the periphery of circular support 11 on axes perpendicular to the planes of edge confining roller sets 12 and 12a, and 15 and 15a. Inside the roll cage there is provided a pay-off roll 22 which is preferably cylindrical in configuration with its axis inclined from the plane of platform 11 at an angle sufiicient to provide clearance of the exiting strip over the sets of convolutions. Preferably, the pay-off roll 22 will be free-running and strip removal will be controlled either by driven exit rolls located beyond the device or by tension exerted by the processing line which follows the accumulator. Thus the inner set of convolutions rotate in response to tension on the innermost convolution from an internal or external tension applying device. The outer set of convolutions will be rotated so as to effectively add strip thereto. The primary consideration is that the motive power for the sets of convolutions does not interfere with the action of the free orbiting loop.

While in the embodiment illustrated in FIGURE 1 the guide rollers 21 are not movable relative to support 11, they preferably will be mounted for movement in a radial path in the manner illustrated in FIGURES 7 and 8.

Each of the rollers 21 has a shaft on which it is rotatably journaled, such as the shaft 23 seen in FIGURE 3. The shafts 23 project downwardly through radially extending slots 24 in support 11 where they are secured to the ends of arms 25 the opposite ends of which are pivotally secured at 26 to the under surface of support 11. Movement of the rollers is controlled by links 27 connected to the arms 25 and extending inwardly to a disk 28 rotatably mounted beneath support 11. A pneumatic cylinder or other actuating device 29 is arranged to rotate the disk 28 between the positions illustrated in FIGURES 7 and 8, thereby moving the rollers 21 radially and hence either expanding or contracting the roll cage 20. With this arrangement as strip is removed from the inner set of convolutions the roll cage 20 will be expanded to compensate for the strip which will have been removed from the inside of the inner set of convolutions. Sensing means, such as a photocell or last loop switch can be provided to effect inward movement of the rollers 21 when the last convolution has been withdrawn from the inner roll cage.

The device is also provided with an outer roll cage indicated by the dashed line 30 in FIGURE 1. The outer roll cage is composed of a plurality of movable guide rollers, indicated generally at 31, which also are movable in a substantially radial path in the space C. As best seen in FIGURE 4, each of the movable guide rollers 31 comprises an arm 32, one end of which is attached to a collar 33, the other end being secured to a sleeve 34. Collar 33 is provided with a bore 35 through which the pivot pin 36 of roller support arm 37 is free to pivot or rock. In the illustrated embodiment of the invention, the support arm 37 mounts a pair of rollers 38 which are free-run- 6 ning and positioned for contact b the strip. While pairs of rollers are illustrated, it will be evident that a guide roller could be rotatably mounted directy to the pivot pin 36.

The seeve 34 at the opposite end of arm 32, while free to rotate, is secured to the base 10 by means of bolt 39, bearings 40 being provided between the bolt and sleeve to facilitate the rotational movement of the sleeve. A sprocket 41 is secured to sleeve 34 and serves as a means for controlling radial movement of the roller assembly. Rotation of sprocket 41 causes arm 32 to pivot about the axis of bolt 39, thereby causing the roller support arm 37 and rollers 38 to move in a substantially radial path.

Movement of the guide rollers 31 may be controlled by means of a link chain 42 (FIGURE 1) which passes around the sprockets 41 and a combined tension producing and chain biasing device having a sprocket 43 rotatably mounted on adjustable bracket 44. Adjustment of the bracket 44 will serve to tension the chain. An arm 45 is fixedly secured at one end to sprocket 43 so that movement of the arm will cause the sprocket to rotate. An actuating means 46, such as a pneumatic cylinder, is connected to the opposite end of arm 45 to move the arm and hence move chain 42 as sprocket 43 is rotated. Preferably the actuating means will normally bias the sprocket 43 in a clockwise direction, the corresponding rototion of sprockets 41 thus acting to move the guide roller 31 inwardly. The pressure of the cylinder 46 may be adjusted so that the guide rollers 31 will be moved outwardly against the bias of the cylinder 46 under the pressure exerted by the outer convolutions as their number is increased. The arms 32 of the guide rollers are of varying lengths and are so oriented that as the rollers are moved outwardly by the incoming strip, the rollers remote from the area in which the strip enters the device will move a greater distance than the rollers close to the entry point. This arrangement compensates for the fact that the guide rollers 47 in the area at which the strip enters the device are stationary so as to provide tangential feeding of the strip which is desirable to insure proper strip feeding without buckling. The rollers 47 are preferably of heavier construction and in the vertical embodiment of the invention serve to support the weight of the outer set of convolutions.

The strip is fed into the device by means of the driven sets of feed rolls 48, and the guide rollers 47 also may be driven. The manner in which the strip is initially threaded through the device can be best understood from FIGURE 5 wherein, as the strip 49 is fed into the device, it is turned inwardly toward the inner roll cage 20 to form the reverse orbiting loop 50. A guide roller 21a forming a part of the inner roll cage 20 will be located to direct the strip toward the pay-off roll 22. If the strip is threaded as described above and as illustrated, there will always be the same number of convolutions in both the inner and outer sets. Although no advantage would accrue, the device will work if one or more convolutions are positioned against the guide rollers 31 before the reverse loop is formed and the strip led around guide roller 21a. In this latter case, the number of convolutions will not be equal in the inner and outer sets but numerical balance will be maintained and, at any stage of operation, the outer set will contain the number of the inner set plus the number originally placed on the support.

Once the strip has been threaded through the device, accumulation occurs in the manner illustrated in FIGURE 6. As the strip feed continues, it will be evident that the incoming strip will build up against the inner faces of the movable guide rollers 31 which define the outer roll cage. Simultaneously, the orbiting loop 50 will move in a counterclockwise direction around the inner roll cage 20, thereby building up convolutions on the inner roll cage. It will be apparent that with each revolution of the orbiting loop, one turn of strip is added to each set of convolutions stored on the device. It will be further evident that as additional convolutions are added to the outside of the outer set, the guide rollers 31 will move outwardly to accommodate the build up in coil thickness. As previously indicated, if the guide rollers 47 are non-movably mounted, the build up in the thickness of the outer set of convolutions is compensated for by the outward movement of the guide rollers 31, with the guide rollers remote from the rollers 47 moving a greater distance than those which are closer to the rollers 47.

With storage achieved by the foregoing procedure, the device is now ready to deliver a continuous strip. As the strip is caused to pass around the pay-off roll 22, the convolutions in the inner set begin to rotate as the innermost convolution passes around the guide roller 21a for discharge. Simultaneously with the rotation of the innermost set of convolutions, the reverse orbital loop 50 begins to move in a clockwise direction, thereby peeling the innermost convolution from the outer set. The peeling action is such that for each convolution of strip removed from the inner set, a portion of a convolution will be transferred from the outer to the inner set. However, the numerical balance between the number of convolutions in the inner and outer sets will remain the same with the number of convolutions in each set diminishing at the same rate.

If, at some succeeding point in time, additional strip is fed into the device, the speed and perhaps the direction of movement of the orbital loop will change. That is, if the lineal speed of strip feed exceeds the lineal speed of strip delivery, the loop will again begin to move in a counterclockwise direction, thereby building up and storing additional convolutions of strip. The movement of the orbital loop is completely self controlling and regulating to accommodate any changes in strip speed.

The controls for the device are relatively simple. While manual operation would eliminate the necessity for controls, the operator simply stopping feeding movement when a predetermined number of convolutions has been accumulated, and resuming strip feed when the number of convolutions has diminished to a specified point, automatic operation requires a minimum of controls. For example, a microswitch 51 positioned near the point of strip entry may be utilized to detect the removal of the outermost convolution in the outer set and activate feed rolls 48 to initiate feeding movement of the strip. Alternatively, this device may comprise an edge-sensing member positioned to detect the movement of the strip edge. It may be so located as to actuate the feed rolls upon the depletion of the outer set of convolutions to any given number of turns.

A second control 52 (FIGURES and 6), such as a a photocell, may be located in advance of the feed rolls 48 to detect the end of the strip before it reaches the drive rolls so that additional strip may be added. Obviously, such control devices may include means for stopping the processing line being fed by the accumulator in the event of a breakdown which results in the presence of insuflicient strip to satisfy the demands of the processing line.

It will also be evident that strip detecting means may be provided to arrest the feeding of strip to the device when a predetermined number of convolutions have been built up in the device. For example, a coacting pair of limit switches 53 and 54, as seen in FIGURE 1, can be arranged in series so as to stop the movement of the feed rolls 48 when maximum accumulation has occurred.

From the foregoing description it should be evident that the instant device permits the automatic accumulation of a substantial quantity of strip material in a limited space. At the same time, the device has a minimum of driven parts and is of simple yet sturdy construction. Its compactness, particularly its ability to be operated in any position from horizontal to vertical, adds to its versatility.

Modifications may be made in the invention without departing from its spirit and purpose. Various modifications have already been pointed out and others will readily occur to the skilled worker in the art. For example, while a preference has been expressed for mounting the guide rollers making up the roll cages for joint movement, they may be made individually movable as by being individually spring biased. Similarly, while free-running edge confining and guide rollers are described, provision could be made for driving the various rollers if so desired. In addition, the device is operable with either an expandable or a fixed inner roll cage, the choice being made in view of the effect of slippage on product quality.

In some situations when accumulating materials which are quite flexible in an accumulator mounted so that the coil is in a vertical plane, it may be necessary to provide additional support for the outer set of convolutions. This can be done in many ways; for example, magnetic energy could be used if the material is ferromagnetic.

The device has been described as having the inner and outer sets of convolutions in the same plane; however, they may be offset slightly to facilitate withdrawal of the strip or some other design feature.

In some situations, the outer guide rolls may be fixed, although this will result in an abrading action. If the outer rolls are not expandable, a narrow range of operation may be accomplished depending upon how much slippage between the outer convolutions takes place before locking-up occurs. Lubrication will assist. This mode of operation may be adequate, for example, if the total input length can be stored at a relatively large diameter with a relatively low number of convolutions.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A method of accumulating strip material which comprises the steps of forming a length of strip into a coil composed of an inner set of convolutions and an outer set of convolutions lying in spaced relation to each other, said sets of convolutions being interconnected by a free reverse loop extending between and joining the outermost convolution in the inner set and the innermost convolution in the outer set, whereby said reverse loop will orbit freely in opposite directions between the said sets of corivolutions as they are rotated, Withdrawing strip from the inside of the innermost set of convolutions by rotating said inner set in one direction and feeding additional strip to the outside of the outer set of convolutions by rotating said outer set in the opposite direction, a numerical balance being maintained at all times between the number of convolutions in the inner and outer sets during both feeding and delivery of strip.

2. The method claimed in claim 1 including the step of increasing the quantity of strip in the coil by feeding strip to the coil at a lineal rate of feed in excess of the lineal rate at which strip is Withdrawn from the coil, and decreasing the quantity of strip in the coil by withdrawing strip from the coil at a lineal rate of withdrawal which exceeds the lineal rate at which strip is fed to the coil.

3. The method claimed in claim 2 wherein the coil of strip is formed with its axis of rotation disposed in a generally vertical plane and said coil is supported from beneath on a surface transverse to its axis of rotation.

4. The method claimed in claim 2 wherein the coil of strip is formed with its axis of rotation disposed in a generally horizontal plane and said coil is supported in part by surfaces parallel to its axis of rotation.

5. A method of providing a continuous supply of strip material in spite of intermittent strip feed, which comprises the steps of forming a length of strip material into a coil composed of an inner set of convolutions and an outer set of convolutions lying in spaced relation to each other, each of said sets of convolutions having a substantially equal number of turns with the outermost turn of the inner set connected to the innermost turn of the outer set by a freely orbiting reverse loop movable in opposite directions solely by reasonof the relative rotational movement of the inner and outer sets of convolutions, continuously withdrawing strip from the inside of the inner set of convolutions, and intermittently feeding additional strip to the outside of the outer set of convolutions, including the step of concurrently adding additional turns to both the inner and outer sets of convolutions during times when the lineal rate of strip feed exceeds the lineal rate of strip withdrawal, and concurrently reducing the number of turns in both the inner and outer sets of convolutions when the lineal rate of strip feed is less than the lineal rate of strip withdrawal.

6. The method claimed in claim wherein additional turns of strip are added to the inner set of convolutions by transferring strip from the outer set of convolutions as the number of turns in the outer set is increased.

7. The method claimed in claim 5 wherein, as the number of turns in the inner set of convolutions is decreased by withdrawing strip therefrom, the numerical balance between the number of turns in the inner and outer sets is maintained by transferring strip from the outer to the inner set.

8. In a strip accumulating device, a strip support for receiving a coil of strip thereon, an inner annular roll cage positioned centrally of said supporting surface, an outer annular roll cage surrounding said inner roll cage and lying in spaced relation thereto, feed means positioned to feed strip material into contact with the inner surface of said outer roll cage, said outer roll cage being adapted to build up an outer set of convolution and said inner roll cage being adapted to build up an inner set of convolutions, the inner and outer sets of convolutions lying in spaced relation to each other with the outermost convolution of the inner set connected to the innermost convolution of the outer set by a reverse loop of said strip material which is freely movable on said support in the space between said sets of convolutions, strip delivery means mounted to withdraw strip from the inside of the inner set of convolutions around said inner roll cage, and means for driving said feed means at an independently variable rate of speed from the rate of speed at which strip is withdrawn from said inner roll cage, whereby the number of convolutions in both the inner and outer sets of convolutions will be increased when the lineal rate of strip feed exceeds the lineal rate of strip withdrawal, and decreased when the lineal rate of strip feed is less than the lineal rate of strip withdrawal.

9. The strip accumulating device claimed in claim 8 wherein at least one of said roll cages is composed of a series of guide rollers at least some of which are mounted for generally radial movement between an inner position and an outer position.

10. The strip accumulating device claimed in claim 9 wherein said radially moveable guide rollers comprise said outer roll cage and are normally biased to their inner position.

11. The strip accumulating device claimed in claim 10 wherein said outer roll cage includes at least one nonradially moveable guide roller positioned to receive strip from said feed means, and wherein the distance travelled by said radially moveable guide rollers between their inner and outer positions varies in accordance with their distance from said non-radially movable guide roller, their distance of travel progressively increasing in accordance with their remoteness to said non-radially movable guide roller.

12. The strip accumulating device claimed in claim 9 wherein said radially movable guide rollers are interconnected for joint movement.

13. The strip accumulating device claimed in claim 9 wherein said radially movable guide rollers comprise said inner roll cage, and wherein means are provided to move said rollers from one position to the other.

14. The strip accumulating device claimed in claim 8 wherein said supporting surface comprises a series of radially disposed edge confining rollers projecting outwardly from said inner roll cage.

15. The strip accumulating device claimed in claim 14 wherein a second series of radially disposed supporting rollers is mounted in a plane spaced outwardly from the plane of said first series of rollers in parallel relation thereto.

16. The strip accumulating device claimed in claim 15 including adjustment means for varying the distance between said first and second series of supporting rollers.

17. A strip accumulating device comprising a planar supporting surface for receiving an edge of a coil of strip thereon, an inner annular roll cage positioned centrally of said supporting surface composed of a plurality of freely rotatable guide rollers, an outer annular roll cage surrounding said inner roll cage and lying in spaced relation thereto, said outer roll cage comprising a plurality of freely rotatable guide rollers, means mounting said last named guide rollers for radial movement during operation to vary the diameter of the roll cage defined thereby, strip feeding means positioned to feed strip material into contact with the inner surfaces of said last named guide rollers, and strip delivery means positioned to receive strip withdrawn from said inner roll cage.

18. The strip accumulating device claimed in claim 17 wherein said planar supporting surface extends in a generally vertical plane, and wherein a second strip edge supporting surface lies in parallel spaced relationship to said first named strip edge supporting surface, whereby strip being coiled is contained between said edge supporting surfaces.

19. The strip accumulating device claimed in claim 18 wherein said strip supporting surfaces each comprises a series of radially disposed strip edge supporting rollers.

20. The strip accumulating device claimed in claim 19 wherein the rollers in said inner roll cage are mounted for movement from an inner to an outer position.

21. The strip accumulating device claimed in claim 20 wherein at least one of said guide rollers in said outer roll cage is non-movably mounted relative to said supporting surface, wherein said non-movable guide roll is at the bottom of the device, and wherein said strip feeding means is positioned to feed strip into contact with said non-movable guide roller as the strip enters said outer roll cage.

22. The strip accumulating device claimed in claim 21 wherein said movable guide rollers in said outer roll cage include means mounting said rollers for movement from an inner position to an outer position, the distance between said inner and outer positions varying as the movable guide rolls progress away from said non-movable guide roll, the rollers having the greatest distance of travel being at the top of the outer roll cage.

23. The strip accumulating device claimed in claim 22 wherein each of said movable guide rolls is mounted at one end of an arm the oposite end of which is pivotally mounted to a support, and linkage means interconnecting the last named ends of said arms for joint pivotal movement.

24. The strip accumulating device claimed in claim 17 wherein said planar supporting surface comprises separate inner and outer strip supporting sections, with the inner strip supporting section positioned to support convolutions of strip formed around said inner roll cage and said outer supporting section positioned to support convolutions of strip formed against said outer roll cage, the convolutions of strip formed on the respective inner and outer supporting sections being independently movable relative to each other, and means for controlling the lineal rate of strip feed relative to the lineal rate of strip delivery, whereby strip will be accumulated when the lineal rate of strip feed exceeds the lineal rate of strip delivery, and the accumulated supply of strip diminished when the lineal rate of strip delivery exceeds the lineal rate of strip feed.

1 1 12 25. The strip accumulating device claimed in claim 24 3,034,399 5/1962 Goepel 24255.19 wherein said inner and outer strip supporting sections 3,341,139 9/1967 La Tour 24255.19 X

each comprises an independently rotatable set of radially disposed strip edge supporting rollers. FOREIGN PATENTS 622,827 12/ 1935 Germany.

STANLEY N. GILREATH, Primary Examiner References Cited UNITED STATES PATENTS 2,318,316 5/1943 Lawrence 242 55.19X U.S.C1.X.R. 2,363,403 11/1944 De Napoli 242 55.19 242-5519, 78.1 

